The present invention relates generally to the field of implantable medical devices (IMDs) such as implantable neurological stimulation (INS) devices, drug pumps, and cardiac pacemakers. More particularly, the present invention relates to implantable medical devices that include titanium alloy housings or casings.
Implantable medical devices typically include external structures (e.g., housings or casings) that are made from biologically compatible materials to minimize undesirable interactions with the human body. One example of such a biologically compatible material that has been used for IMD housings is commercial pure titanium Grade 1 (hereinafter referred to as “CP Ti Grade 1”). This material has several characteristics that make it desirable for IMD housings, including its mechanical properties, which make it possible to form relatively small structures with complex geometries.
The use of CP Ti Grade 1 may not be optimal in all IMD applications, however. For example, certain IMDs may include batteries within their housings that are designed to be inductively charged while the IMDs are implanted. In such configurations, the IMD includes an electrically conductive coil or winding that is electrically coupled to the battery of the IMD. To charge the battery, a “primary” coil or winding from a charging system is placed near the location where the IMD is implanted and a current is sent through the primary coil; through induction, a current is then generated in the secondary coil that is transmitted to the battery.
Where the coil of the IMD is provided within the housing of the IMD, the CP Ti Grade 1 material may not be ideally suited to allow inductive charging. It may be desirable instead to use a material that exhibits greater power coupling efficiency and improved telemetry distance than would be possible if the structure of the device was made using only CP Ti Grade 1. Additionally, because the IMD is typically subjected to various stresses during implantation and use, it may also be desirable to form the housing from a material that has greater strength than CP Ti Grade 1.
It would be desirable to provide an implantable medical device that utilizes a material for its housing that allows for improved power coupling and telemetry distance, and which may have sufficient mechanical strength to provide enhanced protection for the device. It would also be desirable to provide an implantable medical device that utilizes a material that may be formed in a relatively simple and cost-efficient manner at relatively low temperatures. It would be desirable to provide an implantable medical device that includes any one or more of these or other advantageous features as will be apparent to those reviewing the present disclosure.